Generally, a clutch disc is so constructed that a friction facing, secured to a cushioning plate provided at an outer periphery of the clutch disc, is disposed between an engine-side flywheel and a pressure plate interlocked to a clutch pedal. Further, it is so constructed that torque, from the flywheel side, is transmitted through the clutch disc to a central output shaft when the friction facing is sandwiched by and between the flywheel and the pressure plate.
The engine-side torque is transmitted to the clutch, but on the other hand, various vibrations of the engine-side are also transmitted thereto. These vibrations are simultaneously transmitted to the pressure plate through the friction facing, etc. Such vibration cause resonance of the cushioning plate or pressure plate so that a resonance sound is apt to be emitted therefrom in a half-engaged state of the clutch at the time of starting the vehicle.
An object of this invention is to solve the problem of "resonance sound" emitted especially in the so-called half-engaged state during engaging the clutch due to resonance of the cushioning plate or pressure plate.